Electrochemically synthesized Nitrogen-doped Carbon Dots as Fluorescence Nano-sensors for the Selective Screening of Tetracyclines

Electrochemically synthesized Nitrogen-doped Carbon Dots as Fluorescence Nano-sensors for the Selective Screening of Tetracyclines | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Electrochemically synthesized Nitrogen-doped Carbon Dots as Fluorescence Nano-sensors for the Selective Screening of Tetracyclines Daniela Iacopino This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8316466/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The growing release of antibiotics, especially chlorinated variants, into aquatic systems presents serious risks to ecosystems and human health, highlighting the need for rapid, low-cost detection tools. Here we report the first use of nitrogen-doped carbon dots (N-CDs) produced through a simple single-step electrochemical synthesis in water, for simultaneous speciation and quantification of tetracycline antibiotics. The synthesised N-CDs exhibited excitation-dependent fluorescence with dual emission at 425 and 515 nm, enabling two distinct sensing responses within the same probe. All tetracycline, tetracycline (TET), oxytetracycline (OTC) and chlortetracycline (CTC), induced pronounced fluorescence quenching at 515 nm (λex = 410 nm), attributed to a combination of inner-filter effect, and static and dynamic quenching mechanisms. However, CTC also uniquely enhanced N-CDs emission at 425 nm (λex = 350 nm), allowing tetracyclines speciation. Under optimized conditions, the sensor achieved micromolar sensitivity and high selectivity, maintaining performance in complex matrices including tap and river water, with recoveries of 92–117% and RSD < 9%. This sustainable nanomaterial platform offers a simple, robust approach for monitoring antibiotic contamination and supporting safer water management. Physical sciences/Materials science Physical sciences/Materials science/Nanoscale materials N-CDs Carbon Dots electrochemical synthesis tuneable fluorescence fluorescent probe Tetracycline detection Chlortetracycline detection Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SITETPAPER2Updated20251203DIMP.docx Electrochemically synthesized Nitrogen-doped Carbon Dots as Fluorescence Nano-sensors for the Selective Screening of Tetracyclines Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8316466","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":557550914,"identity":"651be839-6917-4992-a512-d41ec4e39baf","order_by":0,"name":"Daniela Iacopino","email":"data:image/png;base64,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","orcid":"https://orcid.org/0000-0003-2301-9401","institution":"Tyndall National Institute","correspondingAuthor":true,"prefix":"","firstName":"Daniela","middleName":"","lastName":"Iacopino","suffix":""}],"badges":[],"createdAt":"2025-12-09 10:35:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8316466/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8316466/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":98436704,"identity":"2b15f3da-b336-42c0-8f7f-6329c4dae280","added_by":"auto","created_at":"2025-12-17 16:56:07","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1357921,"visible":true,"origin":"","legend":"","description":"","filename":"PAPER2TetracyclinesdetectionusingelectrochemicallysynthesizedNCDs20251203DIMP.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8316466/v1_covered_39807564-0379-4911-949d-1f41ad8af956.pdf"},{"id":97842530,"identity":"02748029-c067-48b8-bdf8-efce8efbfb37","added_by":"auto","created_at":"2025-12-10 04:15:36","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1422676,"visible":true,"origin":"","legend":"Electrochemically synthesized Nitrogen-doped Carbon Dots as Fluorescence Nano-sensors for the Selective Screening of Tetracyclines","description":"","filename":"SITETPAPER2Updated20251203DIMP.docx","url":"https://assets-eu.researchsquare.com/files/rs-8316466/v1/78e53d4c2feb6167de75b158.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Electrochemically synthesized Nitrogen-doped Carbon Dots as Fluorescence Nano-sensors for the Selective Screening of Tetracyclines","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"N-CDs, Carbon Dots, electrochemical synthesis, tuneable fluorescence, fluorescent probe, Tetracycline detection, Chlortetracycline detection","lastPublishedDoi":"10.21203/rs.3.rs-8316466/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8316466/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"The growing release of antibiotics, especially chlorinated variants, into aquatic systems presents serious risks to ecosystems and human health, highlighting the need for rapid, low-cost detection tools. Here we report the first use of nitrogen-doped carbon dots (N-CDs) produced through a simple single-step electrochemical synthesis in water, for simultaneous speciation and quantification of tetracycline antibiotics. The synthesised N-CDs exhibited excitation-dependent fluorescence with dual emission at 425 and 515 nm, enabling two distinct sensing responses within the same probe. All tetracycline, tetracycline (TET), oxytetracycline (OTC) and chlortetracycline (CTC), induced pronounced fluorescence quenching at 515 nm (λex = 410 nm), attributed to a combination of inner-filter effect, and static and dynamic quenching mechanisms. However, CTC also uniquely enhanced N-CDs emission at 425 nm (λex = 350 nm), allowing tetracyclines speciation. Under optimized conditions, the sensor achieved micromolar sensitivity and high selectivity, maintaining performance in complex matrices including tap and river water, with recoveries of 92–117% and RSD \u003c 9%. 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